The course of tardive dystonia in Afro Caribbean patients, a population-based study: the Curacao extrapyramidal syndromes study: VII.

Tardive dystonia (TDt) is a severe side effect of long-term use of antipsychotics. Previous publications suggested that TDt persist but the results are distorted by referral bias. In a population-based nine-year follow-up study (one baseline, six follow-ups) of chronic psychiatric patients (N=194) on a Caribbean island, the course of prevalent and incident TDt was measured with the Fahn-Marsden rating scale. Of the 26 patients (mean age 53.3 yrs) with TDt at baseline, 64% recovered, 20% persisted, and in 16% the course was intermittent. The severity of baseline TDt was significantly higher in persistent cases versus those who recovered (t=3.01, P<0.008). Of the 27 incident cases (cumulative 9-year incidence: 16.1%; mean age 57.6 yrs), 80% recovered, 8% persisted, and in 12% the course was intermittent. Predominantly affected were hands, eyes (blepharospasm), neck and mouth. The natural course of TDt is better than previously suggested but severe cases tend to persist.